This invention relates to a stand type image input device wherein an imaging portion is in non-contact with subjects.
In a stand type image input device, a medium to be scanned in is placed on an installation base and the image of the medium is captured. The optical lens thereof is not in contact with the medium and the space between the medium and the image portion is open; in other words, the medium is not fixed. Distortion or defocusing may occur during image input with this structure because of creasing or curling in the medium. The distortion or defocusing causes the recognition rate to be degraded when the characters in the inputted image are recognized.
One method for preventing erroneous recognition is that an image is scanned in under two different conditions, and the scanned-in images are synthesized and developed on a plane. Such a technique is disclosed, for example, under Japanese Patent Laid-open No. 2000-115510.
However, the above technique requires two or more times of image scanning for one time of recognition, and poses a problem of increase in scanning-in time. Further, the capacity of memory is increased for synthesizing, and this leads to another problem, increase in cost.